package com.pig4cloud.captcha;

import com.pig4cloud.captcha.base.Captcha;
import com.pig4cloud.captcha.utils.GifEncoder;

import java.awt.*;
import java.awt.geom.CubicCurve2D;
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.io.OutputStream;

/**
 * Gif验证码类 Created by 王帆 on 2018-07-27 上午 10:08.
 */
public class GifCaptcha extends Captcha {

	public GifCaptcha() {
	}

	public GifCaptcha(int width, int height) {
		setWidth(width);
		setHeight(height);
	}

	public GifCaptcha(int width, int height, int len) {
		this(width, height);
		setLen(len);
	}

	public GifCaptcha(int width, int height, int len, Font font) {
		this(width, height, len);
		setFont(font);
	}

	@Override
	public boolean out(OutputStream os) {
		try {
			char[] strs = textChar(); // 获取验证码数组
			// 随机生成每个文字的颜色
			Color fontColor[] = new Color[len];
			for (int i = 0; i < len; i++) {
				fontColor[i] = color();
			}
			// 随机生成贝塞尔曲线参数
			int x1 = 5, y1 = num(5, height / 2);
			int x2 = width - 5, y2 = num(height / 2, height - 5);
			int ctrlx = num(width / 4, width / 4 * 3), ctrly = num(5, height - 5);
			if (num(2) == 0) {
				int ty = y1;
				y1 = y2;
				y2 = ty;
			}
			int ctrlx1 = num(width / 4, width / 4 * 3), ctrly1 = num(5, height - 5);
			int[][] besselXY = new int[][] { { x1, y1 }, { ctrlx, ctrly }, { ctrlx1, ctrly1 }, { x2, y2 } };
			// 开始画gif每一帧
			GifEncoder gifEncoder = new GifEncoder();
			gifEncoder.setQuality(180);
			gifEncoder.setDelay(100);
			gifEncoder.setRepeat(0);
			gifEncoder.start(os);
			for (int i = 0; i < len; i++) {
				BufferedImage frame = graphicsImage(fontColor, strs, i, besselXY);
				gifEncoder.addFrame(frame);
				frame.flush();
			}
			gifEncoder.finish();
			return true;
		}
		catch (Exception e) {
			e.printStackTrace();
		}
		finally {
			try {
				os.close();
			}
			catch (IOException e) {
				e.printStackTrace();
			}
		}
		return false;
	}

	@Override
	public String toBase64() {
		return toBase64("data:image/gif;base64,");
	}

	@Override
	public String getContentType() {
		return "image/gif";
	}

	/**
	 * 画随机码图
	 * @param fontColor 随机字体颜色
	 * @param strs 字符数组
	 * @param flag 透明度
	 * @param besselXY 干扰线参数
	 * @return BufferedImage
	 */
	private BufferedImage graphicsImage(Color[] fontColor, char[] strs, int flag, int[][] besselXY) {
		BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
		Graphics2D g2d = (Graphics2D) image.getGraphics();
		// 填充背景颜色
		g2d.setColor(Color.WHITE);
		g2d.fillRect(0, 0, width, height);
		// 抗锯齿
		g2d.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
		// 画干扰圆圈
		g2d.setComposite(AlphaComposite.getInstance(AlphaComposite.SRC_OVER, 0.1f * num(10))); // 设置透明度
		drawOval(2, g2d);
		// 画干扰线
		g2d.setComposite(AlphaComposite.getInstance(AlphaComposite.SRC_OVER, 0.7f)); // 设置透明度
		g2d.setStroke(new BasicStroke(1.2f, BasicStroke.CAP_BUTT, BasicStroke.JOIN_BEVEL));
		g2d.setColor(fontColor[0]);
		CubicCurve2D shape = new CubicCurve2D.Double(besselXY[0][0], besselXY[0][1], besselXY[1][0], besselXY[1][1],
				besselXY[2][0], besselXY[2][1], besselXY[3][0], besselXY[3][1]);
		g2d.draw(shape);
		// 画验证码
		g2d.setFont(getFont());
		FontMetrics fontMetrics = g2d.getFontMetrics();
		int fW = width / strs.length; // 每一个字符所占的宽度
		int fSp = (fW - (int) fontMetrics.getStringBounds("W", g2d).getWidth()) / 2; // 字符的左右边距
		for (int i = 0; i < strs.length; i++) {
			// 设置透明度
			AlphaComposite ac3 = AlphaComposite.getInstance(AlphaComposite.SRC_OVER, getAlpha(flag, i));
			g2d.setComposite(ac3);
			g2d.setColor(fontColor[i]);
			int fY = height
					- ((height - (int) fontMetrics.getStringBounds(String.valueOf(strs[i]), g2d).getHeight()) >> 1); // 文字的纵坐标
			g2d.drawString(String.valueOf(strs[i]), i * fW + fSp + 3, fY - 3);
		}
		g2d.dispose();
		return image;
	}

	/**
	 * 获取透明度,从0到1,自动计算步长
	 * @param i
	 * @param j
	 * @return 透明度
	 */
	private float getAlpha(int i, int j) {
		int num = i + j;
		float r = (float) 1 / (len - 1);
		float s = len * r;
		return num >= len ? (num * r - s) : num * r;
	}

}
